21136021345 has 8 divisors (see below), whose sum is σ = 25366199400. Its totient is φ = 16906834560.

The previous prime is 21136021339. The next prime is 21136021369. The reversal of 21136021345 is 54312063112.

It can be written as a sum of positive squares in 4 ways, for example, as 1922734801 + 19213286544 = 43849^2 + 138612^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21136021345 - 2⁷ = 21136021217 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 200070 + ... + 286879.

It is an arithmetic number, because the mean of its divisors is an integer number (3170774925).

Almost surely, 2^21136021345 is an apocalyptic number.

It is an amenable number.

21136021345 is a deficient number, since it is larger than the sum of its proper divisors (4230178055).

21136021345 is an equidigital number, since it uses as much as digits as its factorization.

21136021345 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 495635.

The product of its (nonzero) digits is 4320, while the sum is 28.

Adding to 21136021345 its reverse (54312063112), we get a palindrome (75448084457).

The spelling of 21136021345 in words is "twenty-one billion, one hundred thirty-six million, twenty-one thousand, three hundred forty-five".